Yes, multiple times (I think it's a User Error - i.e. my poor skills)
I think that the issue is that I am terrible at modeling. My models look cool, but perform terribly. Even though I've been using this tool for probably 4 years.
And, I am not good at making sure my UVs are set up well (one UV looked insane and not mapped well at all).
Plus I have a hard time getting rid of hidden faces (see item 1)
Lighting in Unity is extremely difficult. I'm stopping everything and trying to learn it properly based my post above.
This almost makes me want to drop Unity and switch to Unreal Engine.

Also, I apparently need to learn how to do the UV mapping in Probuilder so that my super basic grey-box models don't have crazy UV layouts that take up so much space. This could also be part of the issue.

Don't worry about it anymore. I'm going to go through the Unity Lightmapping old tutorial they have where it comes with a project and just figure out what the hell I'm doing wrong.
https://unity3d.com/learn/tutorials/topics/graphics/introduction-precomputed-realtime-gi?playlist=17102

Hello,
I'm having a light bleed through issue (again). I thought this was fixed. I searched the forums and could not find a solution. I'm using Unity 2017.1 and the correct version of PB for that (2.9.7f5 - just downloaded an updated copy from this site about a week ago). I've spent too much time trying to figure this out. I'm just trying to build a demo scene with indoor and outdoor for a FPS type multiplayer game to use with an Asset I'm creating. Basically, I'm going to leave the scene grey-box with some different vertex colors on buildings for orientation.
The screen shot below is from the inside of a super basic building looking up at a corner. Left wall would be the back of the building, right wall is a side wall, and top wall is the ceiling (which is it's own object). I know it's not an issue to do with separate objects, because my other building has the same issue and it's all one object.

Received two warning message on a brand new, fresh project. All I have loaded on the project is all of the ProCore tools (Builder, Grids, Groups, Brush, Decals, QuickEdit). Unity Version 2017.1.1.1f1. Please clean it up for the next release.
Below is the Warning Message 1.
Assets/ProCore/QuickBrush/Editor/Windows/qb_Painter.cs(1719,13): warning CS0618: `UnityEditor.Handles.ArrowCap(int, UnityEngine.Vector3, UnityEngine.Quaternion, float)' is obsolete: `Use ArrowHandleCap instead'
Below is the Warning Message 2.
Assets/ProCore/QuickBrush/Editor/Windows/qb_Painter.cs(2581,24): warning CS0253: Possible unintended reference comparison. Consider casting the right side expression to type `UnityEngine.Object' to get value comparison

Received a warning message on a brand new, fresh project. All I have loaded on the project is all of the ProCore tools (Builder, Grids, Groups, Brush, Decals, QuickEdit). Unity Version 2017.1.1.1f1
Below is the Warning Message. Please clean it up for the next release.
Assets/ProCore/QuickDecals/Classes/qd_Mesh.cs(34,38): warning CS0618: `UnityEngine.Renderer.castShadows' is obsolete: `Use shadowCastingMode instead.'

Here's some shots from a scene I just made real fast.
Exterior - The cube is lighter than the Plane (Plane is on the right). Same texture
Interior - There are two shots of this. One with the Light baked and on, the other with the Light disabled and only the Directional Light is baked.